SAF,
The Vault Media Usage Report,
shows off site media trends for selected vaults and current off-site media count. The report consists of two component reports, a bar chart and a table.
The report helps with off-site media trending.
When running the report you can select the vaults your want to be included.
The bar chart shows the weekly trend of off-site media count for the selected vaults.
The table provides the details of vaulted media for the selected vaults. (Media ID, off-site slot number) container ID, expiration date, barcode, etc...
If this is coming back blank, I would suspect 1 of a few things.
1) No Vault has been configured in NetBackup
2) Data Collection has failed for media data type.
3) Data Collection has failed for the master due to version mismatch. (OpsCenter 7.5 and NBU 7.5.0.4) - as Ron Described.